Processing of Alumina Production Red Mud Sinter to Produce Solutions for Carbonation

The present study addresses the first stage in the development of a processing technology for low-grade high-silica bauxites aimed at producing solutions suitable for carbonation. The proposed process includes Bayer leaching of bauxite to obtain sodium aluminate liquor and red mud, followed by sintering of the red mud with limestone and soda ash. The resulting sinter is then leached with a recycled soda-caustic solution to produce an alkaline aluminate liquor and a residue. The alkaline aluminate liquor obtained from sinter leaching is subjected to carbonation to precipitate aluminum hydroxide, which is subsequently used as seed material during the decomposition of Bayer sodium aluminate liquor. The proposed technology reduces the volume of aluminate liquor directed to the Bayer decomposition stage while maintaining aluminum hydroxide yield, thereby improving the efficiency of the decomposition process.